Device for safeguarding internal combustion engines against excessive speed and lubrication failure



Oct. 28, 1941. N. K MAYBACH DEVICE FOR SAFEGUARDING INTERNAL COMBUSTION ENGINES AGAINST EXCESSIVE SPEED AND LUBRICATION FAILURE Filed April 7, 1959 2 Sheets-Sheet 1 28,1941. K. MVAYBACH 22605576 DEVICE FOR SAFEGUARDING INTERNAL COMBUSTION ENGINES AGAINST 'EXCESSIVE SPEED AND LUBRICATION FAILURE v Filed April 7, 1959 2 Sheets-Sheet 2 him/0r.- B M v 'Patented Oct. 28, 1941 I I v i v 2,260,576 nEvIcE Eon SAFEGUARDiNG INTERNAL, COMBUSTION ENGINES AGAINST ExcEs- ,SIVE srE n ANn LUnaIca'I'IoN m Mums,

Friedriehshaien-on -the noden see, Germany, assignor to- Maybach-Motoren-' ban "Gesellschait lit boschrankter Haftung;

. Frledrichshaien-on the-hodeuee, Germany Application April}, 1m, ierialNo. 286.628.

In Germany A a-1114 1938 The invention relates to asaiety arrangement for internal" combustion engines, in particular of automobile vehicles, in" which the regul ting member -tor the output -01 the engine can'be' influenced on the one handby the 'driver'o! the 1;;

vehicle and on the other hand by actuating arrangement operatedby oilgpressur'e.

According to the invention; theactuating 1: rangement is so constructed that it adjusts the engine to alow outp t as soon as the oil pressure has fallen to a value which is too lowior the operation. The pressure is transmitte to the actuating arrangement by a control' memher moved by a autumn governor. certain speed, the pressure or the oil' is relieved in the actuating arrangement and adiustment'to a lower speed is thereby also effected.

The" arrangement is preferably constructed in such a' manner that a transmitting device de- 20 an electrical control by which the control membe: isactuated. This arrangement preferably pendent upo'nthe speed of the engine influences 'adiusts the speedto a low value which is pret-' erably equal to that also automatically adjusted in the event of shortageot speed oi 1000 'or l500"revolutions per *minute with a maximum normal speed of about 3000 revolutions per minute. 1 I

The arrangement may be such that an indicating arrangement is provided or between the normal maximum even in exceptional cases. The known similar safety arrangements either only prevent a eer-. tain speed from being exceeded or produce warning signals or veven stop the motor in'-the event oi! shortage o1'l bricating oil. The known arrangements are open to the disadvantage that "the warningsignals are either not observed'at all or areonlylobarved too late ,by'the driver of the vehicle. Moreover,' the stopping or the driving engine cannot'in circumstances be permitted; for exampl it avehiclewere travelling within a somewhat long column or ye;- moles,- tne suadens ovvasegor the drive of the vehicle might causea collision; disadvantages are overcomeby' the arrangement ac- 'cording'to, the invention. "In driving "engine's or automobile vehicles which are provided with 'Above' a l5 'changing,-,a' speed range'lying above thisspeed oil, for example a peed a the maximum speed which also must not be exceeded ling within 'aseries ot othefvehicles to avoid collisionand to drive the vehicle concerned to the side with reduced engine' outputi v The arrangementaccordingto theinvention is 5 particularly suitable for vehicles withwhich it is not possible-for the driver todetermine from the sound of the engine'the gear inwhichthe vehicle is travelling. It can' therefore advantageously also be such that the exceeding '01 {the maximum speed permissible during operation,

'ior'example 3000 revolutions per minute, is'; indi-' "cated byspecial markings on the'sp'eedometer 'or by an optical or acousticmignal. bile-hit in exceptional cases, for example d 3m I permissible during normal operatiomdor. example one extending upto a speed b18500 revolutions perminute, may be employed by the driver while at the same-time a warning isgiven by the aforesaid signal, whereaiter the arrangement according to the'inventicn responds at'3500 revolutions per minute and prevents this speed from being further exceeded by throttling the engine.

Inthe case of" other yehicles'imwhieh it is impossible or difflcultto verify the speed by means 0! optical signals orby reading the oil" pressure "from, pressure meters. s flicker. lamp *i'sadvantageously provided which. is automatically switched on when'the maximum speed permis- 8'0 'sible during normal operation is exceeded. The

continuous fluctuations ot 'the, la'mp light-"have a certain disturbing efiect'on the [eyes of the "driver'ot thevehicle, so that his attention is g I rapidlydrawnto the-fact that heis driving at- 85 aspeed which isgr'eater-'than the maximum H sp ed permissible during normal-operation.

, Furthermore, the control membermay accord-- mg to theinvention beconst'ructed ass-pressure regulating "valve of known type, so-that this- 10 "valve impartsftothe pressure mediuma pressure wh h, n r n s to, h 'me n 'speed. This pressure actuates a locking member which produces the I g w oil in the actuatingarran'gement for themember 45 femtmgame output of the-engine; The control member. i the W .flmewfm'fprerembly controls the'pressure oufiwmen is made to :act

on the locking member. wThis arrangement is distinguished particularly by the fact that the the safety arrangement according tothe inven- 50 re ure m d 'only a t act, indirectly tion. absolute security is aflorded on the-one hand against any damage owing to shortage of oil and on the other against due to bly high speeds. j .At,,the sanie j time. ,it is also possiblewhen such a vehicle is travelon theicon'trol member. The advanta e is thus secured that'only a simple small regulator havreduction in" the pressure or the s V ry sensitive and r m p d yto speed fluctuations,-

" 7 pie connection of the arrangement according 'to theinvention'is such a device for indicating during normal operation and for the 1 and 30 are; discharge, 1 pipes ;communicating,

. x l rw h he eri r-1 t en ine c i the exceeding of theimaximum speed permissible range between this speed andj the maximum speed permissible inextreme cases afiords .particular' ;ad-

vantages in the case of vehicles of the'aforesaid nature. Such. an arrangement ,permitsthe ex-, ceeding of the maximum speed travelled at during normaloperation within certainlimits for start'-,

At the same ing, gear changing and thelike; time, exceeding of the maximum speed per-' ing to the sound of the engine. Furthermora reliable protection against damage to the bearings due to lack of lubricating oil orv pipebreakage' are diagrammatically shown, mostly in section, in

the accompanying drawings.

ures and 2, -1. is o ;a centrifugal governor driven by; the {engine and actuatinga slide valve 1, and 3' is aspring'bearing onthe one-hand againstya 1 fixed'abutmenticoverj [and on theotherhand iaacae'ro v p I meter ",which indicates the value thereof. a For; 7

the discharge of oil which, owing to leakage at the piston l2, passes to the space to-the right 9 of'this p ston, there is provided a pipe 29,'which, .communicatescin-known-manner with the interior Io'f theenginefcasing. 1 I a Iffor any reason (pipe breakage or lack of oil) 7 r a the'oil pressure falls below the value necessary for f r the safe, operation of the engine, the pressure in the space of;tl'iefcylinder II also falls, correspondingly; Thespring It is so dimensioned that",

' if th'eoil pressure falls below the lowest permissimissible in extreme cases is prevented. even if'it is:

not possible to judge the circumstances by'listenis afforded, while it is possible toplace the vehicle 1 Therefore, the 7 the constructional examples shown against a. disc fi connected to the slide valve-LLB -7 isga feed pipe connected'tothe lubric'ating ,oil pipe ofzth'' engine, and l, ,a control conduitih the slide valve 2,,which conduit hasin its lowejrpart an extension! to the left-handsidet, 8" and ID are further pipes icarryin'g the; lubricating oil. jll isacylinde ytowhich the pipe 8 is connected and-in which there isjadaptedtmmove a. piston 12 which vis connected toa rod i3 and is loaded 15 is a double arm lever, one arm,

by a sprin "I8 of whichis connected tothe rod l3=, while. the

other arm," thereof has at 18. [9 is an oil pressure metern zu iskpart of'a carburettor, the throttle valve-2 I ofwhich-isactuatedby the lever 22, to which is connected the rod 23of the usual carburettor rod systemactuated bythedriver of the .vehicle. At

"the right hand end of the rod '23 issituated d s -24,;again st which bears, a spring 25, whichis-argrangedina' casing zi connected to the. further rod 2-1 of..the rod system of thecarburettor.-. 3 1

The arrange .inathe ifollowing manner;

its end a stop surface that admiss'ionof lubricating oil jfro purine no ma O e ati i, th d iving "tam of a vehicle which is connectedstogthe arrange:-

ment, illustrated, 1 the individual positions shown in the figure.

which is suflicient; for supplying the lubricating points of thedriving engine, this pressure is trans;

, v pipe Unto. thespace ofthe cylinder .Ii andholds mittedthroughthepipefi, thejconduit 1 and'the the piston." .in the rightvhand terminal position shown; against the pressnre of the spring ll. ;The.stop surface l8 connected through the rod i3 iand the lever l 5 to the pistonllissituated, as is :shown'inthe figure, at a small'distanoecfrorn the rod-*system'of thegcarburettor when the'latter is- 7 so adjusted by thev driver of the .vehicle that the p throttlevalve 2| is fully open. The oil pressure 1 is transmitted through the piped (Lto the pressure l i n 1 a M soon asthepressure .v the ubricating ,oil-has r'ea'ched .a value ble value the'piston 'il is forced to theleft by the carburettor mayremain in the they are adju sted by. the driver of the vehicle. g I Whenithenthrottle valve is in thezposition; 2i},

,such a quantity ofrgas mixture isfed to theengine i that, it} operates at-a low output; for example at about-10% of the-fulloutput. Ihis positionjmav n m -cas ev c res on 4 runningadjustment. :lhe driver of the vehicle, ,whonotices'the disturbance; owing to theredu'c- ,tion inthe speedof travel, will then drivehis "vehicle out, of the olumnto the o; he sua mQ Qthe'defect Ifi-thespeed of. the driving engine extends inadmissible value," the. pressure of the spring) is overcome by; the. centrifugal force actin gon.,the' weights -of' the centrifugal governor-- l,-whereby the slide valve} is carried so far. t'oi thg' right to the; pipe 8 through; the con uit; 1] is prevented.

Atthef-same time, the upper mouthlof'thepconduit is moved into a position in frontofthe,outlet'con- .duit 30. The communication betv'veen'v the con du it l and the pipe Bis 'mairitaine'dlby {the exten pipe 0 and in'thel space ofthe cylinder :li isirelieved" throu h-thev communicatio'n with thepipe 39,,andthe V oil contained in thes'pacelof,the'cyIinder .l l and in the pipe 8' rod system, 15 and 18,

speed" or ,the' engine an of "the "speed 'oftravel,

. th'e driverfs attention "is f drawn to] the fact that todrive pan inadmissibly, high and, that lower speed. is required. .E Venfif he takesflnogaction"to reducefthespeed, ai e r d c i or t ei p :meenenet eix I 'pressurejof'thefspring i'againflovercomjesthe opli' o i s t me i e li cib h t trifum force of .th'e'we'ights of thefcentrifugalgovernor. g l ,s'ojthat .th'e slidevalve 2 is again returnedto the. illnowfagain establish h pipes n s rou h i c ns s 1 ol i h ex enfi h t h 'arrafie: menu in equilibriumithatjisl'to'say the speedis so high that the throttlelvalvef2jli1of.,the care I ajsufllcient'extent'lby the oil pressure obtaining in the spaceofthe cylinder] .he FhasQendeav'O'ured burettor; is held open" to.

sid Stop and re flowsw y tll p 1' f a ,and consequently into the engine-casing; The f piston ilmovesto the left underthej press'ure'of fthe'spring H; The'thl'ottle valvellor thejcarfburettor is closed by 'the I 7 whereby the speed of the engine; is" correspond ingly'reduced. Owing tothe reductionof ith'e 155 entshownj in Figure 1 operates 1 1 I maintalnthecorrespondingspeedjof equilibrium. -I i1 j T lnstea' of the arrangement-comprising the cone jm gbefl ebe men ewe emiemde a rangement it may readily be understood and is known.

. contact member 4!.

the individual parts.

be employed in which the centrifugal governor l acts directly upon the throttle valve 2|. This arhas not been particularly shown-, as

" In the construction shown in Figure 2, 2' is a pin actuated by the centrifugal governor'i andv arryi s at its right-handend an electrical contact member 21 connected to the battery I2. I} is a control spring and ll is a stop. 22 and ll are two contact plates one of which Ills connected to a flicker lamp connected to a coil 42 in-which When the speed permissible during normal opll, while the other "is v an iron core Q2 is displaceable and is connected'to the control memarcane v eration is exceeded, thepin 3| ismoved to the right by the centrifugalgovernor I. The contact member I'l encounters the contact plate llv and switches on the flicker lamp I. when the speed is further increased,- the contact member ll is displaced to the rilht 22.. Finally, the contact member whereby the iron core the slide valve 2 is carried with it to the right. The oil is thus discharged from the space of the cylinder II in a manner similar to that described above and the throttle valve 2| is closed to a more or less great extent.

In the constructional example shown in Figure 3, I is a centrifugal regulator driven by the engine and moving the control member 2 against the action of the pressure spring 2 into the cylinder 4. The cylinder 4 communicates through the aperture l with a further cylinder I in which the locking member I is moved against the action of the spring 8.

ll is a feed pipe connected to the lubricating oil pipe of the engine. into two branch pipes II and I2. The branch pipe Ii opens into the cylinder 4 via the annular conduit i2, while the branch pipe 12 opens into the cylinder I. The cylindrical wall of the control member 2 is provided with apertures l4 and the locking member groove It. Apertures I serve for the discharge of the pressure medium into the casing. The .cyllnders'i and I! communicate with one another through a conduit It. A piston 2| is moved in the cylinder it against the action of the pressure spring 22. The piston 2| is pivotally connected to a rod 22. which islinked to one arm 2i of a 1 is provided with an annular along the contact plate 21 meets the The coil I2 is thus excited, I 43 is pulled to the right and l v the right into the cen -'corresp0ndins to This feed pipe is divided up in'the space i equilibrium with-the in combination with the I Spring ,3.-

soonasthe oil "the action ned that at apredetermined speed of, thedriving engine and, consequently of" the governor I, the slide valve 2 is moved to theleftby the action of-jthecentrlfugal rorce 'ot the'governor Oil can then now from the pipe I I through the apertures l4 tothe spacei'l 'and fro'm -there throrrghthe aperture-I locking mem-. ber I x,

r'ding to the action' of thecentrifugsl pendulum l on the control rnember lt there is set M :an' on which mamcentrifugal governor ;action of the I1 is reduced below the value of the centrifugal governon the'slide;

somewhat to the left; so" ll, whereby the valve 2' is moved more oil "can flow from the pipe pressurein the space "I! isia'lain increased-so that itovercomes the action of thecentrifugaiv governor I and'again moves the slide valve 2 .'to'

position. WhenL-the presurefin the space i! is higher than the'value the action of the centrifugal governor, the slide valve 2 is moved from the central position shown, to the right, so that some oil can flow away through-the apertures l4 and the annular conduit II. The pressure in the space ll thus falls, so that the slide valve 2 is returned into the central position (position of equilibrium) owing to the fact that the action or the centrifugal governor is overcome. Therefore, the centrifugal governor I sets win the space I! an oil pressure dependingupon the existing speed. Upon increase or decrease in the speed, the oil pressure obtaining in this space becomes greater or smaller. It at a predetermined speed the oil pressure set up in the space I] is sufiicient, it moves the locking member I rapidlyto the left against the action of the spring I. In this'way, on the one hand the supply of oil from pipe I2 is cut of! and on the other hand communication is established between the space I! and the discharge aperture 22] through the conduit II in the space I! is relieved of pressure so that the two-armed lever, the other arm-2i of which has as its end a stop surface 20.

28 is part of a carburettor, the throttle valve 20 of which is actuated by the lever 22, to which the rod ll of the usual rod system of thecarburettor is connected. To the right-hand end of the rod 2| is connected a disc there presses a spring 24 arranged in the casing a. The casing 32 is connected to the rod ll of the rod, system of the carburettor, which is actuated by the driver of the vehicle. I

22', against which The arrangement operates in the following spring I in the control member 2 is so dimem piston 2! is moved rapidiyto'fthe left under the action of the spring 22-." Theregulating mem-. ber 28 of the carburettor 28 is thus closed through the rod system 22, 24, 2! and the lever 10 and the adjustment to a low speed is eflected.

If there is no or insufiicient oil pressure in the lubrication oil pipe in the engine while running, the piston 2| is influenced in the sense of the .closing of the regulatlngarransementunder the action of the spring 22 to an extent corresponding to the low oil pressure. I

I claim: p

l. A safety device for internal combustion engines lubricated by oil supplied under pressure,- comprising a fluid-pressure-operated device connected to the high pressure side of the lubricating oil system and adapted to operate upon a member for regulating the output of the engine to cause the latter to run at a low speed when; the oil pressure falls to a predetermined low value, a valve connected to said iiuid-pressure-' operated device so as to be capable of operation to reduce the pressureof the oil therein, and a speed responsive device driven from the engine and connected to said valve so as tooperate the mission system.,

c c u i necteci' by an trans 3.-'A safety device for, internalcombustion ent I .gines lubricated by oil supplied under pressure,

comprising a fluid-pressure operated devicej connected to the Kh pressure side otthelubricating on system and adapted to operate upon a memher for regu1ating the output of-the en ine :5 -fl 5. A-saiety device. for internal combustion eiizines lubricated by oil suppliedunder-pressure,

justthe output to a low value when theoil' pressure falls to an inadmissible:value,-a valve connected to said fluid-pressure-operated device so -as to-becapable or operation to reduce the pressure of the oil therein, a warning deviceand a .speed-responsive device driven from the engine and operatively connected to-said valve and said warning device so as toroperatethe latter when p the normal maximum speed is exceeded and: to

. operatethe former when the. maximum spe ed 'perm'issib1e'even in exceptionalcases is exceeded.

4.;A,-safety device as a claimed in claim 13 in which said warning device'is anelectric flicker comprising a' fluid-pressure-operated device .con-

member {or regulating the output otthe engine to addust theoutputto alcw value when the oil pressurefifalls to an inadmissible value, a. fluidpressure-operated valve connected to said fluidv pressure-operated device so as to be cabable' or reducing the pressure of theyoil therein when 01)- erated, said valve receivingtoil asoperating fluid through a conduit connected to the high pressure side oi'the lubricating oil system and through a pressure-reducing :valve and a speed-responsive device driven from the engine and acting upon said pressure-reducins valve sothat the reduced pressure varies with theenginespeed and at a predetermined speed attains a pressure capable of operating said fluid-pressure-operatedvalve.

' miss-cal? nected to s-the high pressure side. .ofthe 1ubrl"- cating oil system and adapted to operate upon a c 

